Exemplary embodiments of the invention relate to a self-retracting and damping device for a drawer element having a first driver, which has a first driver fork for the engagement of an external activator and which is displaceably guided in a first guide curve, and having a second driver, which is displaceably guided in a second guide curve. In this case, one of the drivers is coupled to a damping element and the other of the drivers is coupled to an energy storage unit, wherein the two drivers are coupled together in part. Exemplary embodiments of the invention also relate to a piece of furniture or a domestic appliance with at least one drawer element.
Self-retracting and damping devices are used for a damped active retraction of a sliding element into a retracted or an extended end position. Suitable sliding elements are, for example, movable furniture components or movable elements of a domestic appliance such as a drawer, an appliance carrier or a food carrier. The sliding elements are usually mounted on a guide device, such as a pull-out guide, so that they can be pulled out of a furniture body or an interior space of the domestic appliance. Domestic appliances in this sense are in particular refrigeration appliances, for example refrigerators or freezers, but also cooking appliances such as ovens or steam cookers, and dishwashers. Sliding elements are also movable doors, furniture doors as well as living room doors or room dividers with folding doors, which are mounted on a guide rail via guide elements. Alternatively, the sliding elements can also be used in workshop trolleys, in the medical sector or in pharmacy cabinets.
For comfortable operation of the sliding elements, the self-retracting and damping devices mentioned above are provided, which dampen a movement of the sliding element into an end position and pull the sliding element into this end position. For this purpose, at least one external activator is mounted either on the moving sliding element and/or on the guide device guiding this element, which activator is connected to a driver of the self-retracting and damping device correspondingly on the moving sliding element or on the guide device guiding this element, so that accelerating and/or decelerating forces can be transmitted between the self-retracting and damping device and the sliding element. The self-retracting and damping device may be integrated into the guide device or mounted as a separate unit within the furniture body or the interior space of the domestic appliance to couple with the external activator.
The self-retracting and damping device may be associated with the fixed part of the furniture item, domestic appliance or guide, in which case the external activator is located on the movable drawer element or on the movable part of the guide. However, the arrangement may also be reversed in such a way that the self-retracting and damping device is located on the movable drawer element or on the movable part of the guide, while the external activator is associated with the fixed part of the furniture, domestic appliance or guide.
Self-retracting and damping devices are known that have a driver that is displaceably guided in a guide curve and which is coupled to both a damping element and an energy storage unit. In this case, damping forces and the self-retracting forces applied by the energy storage unit act over the same displacement path of the one driver, unless the damping element provides damping only for part of the displacement path due to its internal structure.
In addition, a self-retracting and damping device is known from the publication KR 2012 000 2183 A, in which two separate drivers are each guided in their own guide curve. A first driver is designed for coupling with the external activator. This driver is guided in a longer guide curve than the second driver, which is coupled to a self-retracting spring. In a first movement section, only the first driver moves with the activator and dampens the movement of the drawer element in this movement section. After this first movement section, an internal driver arranged on the first driver engages in a driver fork of the second driver so that the first and second drivers are coupled together, wherein the external activator still engages in the driver fork of the first driver. This is followed by a second movement section in which damping takes place together with a self-retracting mechanism until the drawer element has reached the retracted end position.
In some applications, in particular for drawer elements of cooling appliances or also for drawer elements which engage in a locking element in their fully retracted position, a movement sequence of a self-retracting and damping device is advantageous in which the greatest possible forces act at the end of the retraction path in order to achieve the safest possible retraction into the fully retracted end position of the drawer element. Self-retracting and damping devices cannot do this according to the prior art described. This also applies to the fully extended end position if, for example, a sliding element designed as a drawer, device carrier or food carrier is unloaded or loaded in this end position. Then it is advantageous that the sliding element remains safely in the fully extended end position. In order to achieve this goal, separate mechanisms with additional components are necessary in the prior art.
Exemplary embodiments are, therefore, directed to a self-retracting and damping device providing the greatest possible self-retracting forces when traveling into the fully retracted and/or extended position of the connected drawer element in order to ensure retraction into the end position of the drawer element. Exemplary embodiments are also directed to a piece of furniture or domestic appliance with such a self-retracting and damping device.
A self-retracting and damping device according to the invention is characterized in that the first driver is coupled to the energy storage unit and the second driver is coupled to the damping element, wherein in a first section of a retracting movement the energy storage unit and the damping element act on the external activator and in a second section of the retracting movement only the energy storage unit acts on the external activator.
As a result, a coupled drawer element experiences a damped self-retracting movement in the first section when it is pulled into the end position. At the end of the first section, the coupling between the first and second drivers is released and the remaining second section of the displacement path of the self-retracting and damping device occurs in a non-damped manner, so that only the self-retracting forces act. This second section, in which the self-retracting and damping device no longer acts in a damping manner, leads to a safer reaching of the end position for the coupled drawer element. At the end of the second section, the first driver and thus the external activator are retracted as far as possible into the self-retracting and damping device.
One reason for this lies in the friction losses switched off in the second section, which the damping element itself introduces into the motion sequence. Another reason is that the damping element keeps the retraction speed low, which is basically desired, but especially in the last section of the self-retraction there is a danger that the drawer element will move from a sliding or rolling friction in its pull-out guide into a static friction that interrupts the movement.
The slightly increased retraction speed, due to the decoupling of the damping element in the second section of the displacement path, prevents the stop of the drawer element by the commencement of static friction instead of rolling or sliding friction when guiding the drawer element. With the self-retracting and damping device according to the invention, the self-retracting function and the damping function are each assigned to one of the drivers. The coupling between the drivers can be clearly determined mechanically by design. In this way it is possible to specify the ratio of the length of the first or second section to the total travel distance.
The preferred length of the second section is between 20% and 40% and in particular between 30% and 35% of the total displacement of the first carrier. The total displacement path corresponds to the sum of the length of the first and second sections. In typical applications, the specified conditions represent a good compromise between sufficient damping and safe insertion into the end position.
In an advantageous embodiment of the self-retracting and damping device, the second driver has a second driver fork to interact with an internal activator arranged on the first driver to couple the two drivers together. In the first section of the retraction movement, the first driver with its internal activator preferably engages in the second driver fork of the second driver in order to couple the two drivers. At the end of the first section, the second driver is guided through the second guide curve in such a way that the coupling between the two drivers is eliminated in the second section of the displacement path. This can be implemented in a constructively simple and reliable manner in that the second guide curve has an angled end section in the transition area between the first and second sections, with the angled end section pointing away from the first guide curve. A retraction of the second driver (or part of the second driver) into the angled end section moves the driver fork at least on one side away from the internal activator, which is then released and can move further into the second section of the retraction movement.
In another advantageous embodiment of the self-retracting and damping device, a detent means is arranged in the area of the angled end section of the second guide curve, which fixes the second driver in the end section. This prevents the second driver from slipping back out of the angled end section, especially if the angled end section is pointing downwards due to gravity.
In a further advantageous embodiment of the self-retracting and damping device, the energy storage unit has at least one tension spring and/or at least one compression spring. The above springs can also be combined, for example by the energy storage unit having a tension spring and a compression spring which are connected to each other via a coupling carriage which is guided in a sliding manner on a housing of the self-retracting and damping device. This combination enables a long displacement path of the first driver with a short installation length of the energy storage unit.
In a further advantageous embodiment of the self-retracting and damping device, the damping element is a linear damper. In principle, other types of damping elements, e.g., a rotary damper, can also be used, but a linear damper is advantageous for a linear displacement movement of the second driver.
In a further advantageous embodiment of the self-retracting and damping device, the second guide curve has at least one evasion section running obliquely to the main guide direction to enable an evasive movement of the second driver in a direction transverse to the main guide direction. Due to transport or installation, a situation may occur in which the internal activator of the first driver is not positioned in the second driver fork, although the first driver is in the first section of the retraction movement. In order to be able to move the internal activator back into the second driver fork, the evasion sections are provided in the guide curve. Preferably, the second driver has a spring lance protruding into its travel, which exerts a restoring force on the second driver during the evasive movement. This results in a resilient evasive movement. When the two drivers are correctly positioned again due to the evasive movement, the second driver springs back and the second driver fork grips the internal activator positively again to establish a coupling of the two drivers.
In a further advantageous embodiment of the self-retracting and damping device, at least one edge of the second guide curve is designed to be flexible in sections in order to enable an evasive movement of the second driver in a direction transverse to the main guide direction. This alternative embodiment also allows an evasive movement of the second driver in order to correct an incorrect positioning of the two drivers. If the second guide curve is formed in a wall of a housing of the self-retracting and damping device, compliance can be advantageously achieved by one or more incisions formed adjacent and preferably parallel to the second guide curve in the wall.
A piece of furniture or domestic appliance according to the invention having at least one drawer element is characterized in that it has at least one of the self-retracting and damping devices described above acting on the drawer element. In this case, the self-retracting and damping device can be stationary relative to a body of the furniture or domestic appliance and interact with an external activator connected to the drawer element. Alternatively, the self-retracting and damping device may be located on the drawer element and interact with a stationary external activator. This results in the advantages mentioned in connection with the self-retracting and damping device.
The self-retracting and damping device according to the invention can be used for any end positions of the drawer element. The particularly advantageous application serves to retract the drawer element into a retracted closed position within the piece of furniture or domestic appliance. In the same way, it is also possible to use the self-retracting and damping device to retract the drawer element into an open position, in which the drawer element is brought into its extended end position outside the furniture body or domestic appliance. For example, two or more self-retracting and damping devices can be combined to retract and dampen a drawer element in both the closed and open positions.